Electrical hand tool device

ABSTRACT

The invention concerns an electric hand tool device, in particular, a percussion drill or a drill hammer, comprising a spindle ( 10 ) that can be driven by a drive motor and cooperates at one end ( 12 ) with a tool support, and a percussion means ( 24 ) for axially moving the spindle ( 10 ) in a percussion position, wherein an adjusting means ( 42 ) is provided for adjusting the spindle ( 10 ) between the percussion position and a rotary position, the adjusting means ( 42 ) comprising a switch ring ( 44 ) which is disposed on the spindle ( 10 ) and has cam configurations ( 46,48 ) on both end faces thereof, wherein one of the cam configurations ( 46 ) can engage in a corresponding cam configuration ( 52 ) which is fixed to the housing through turning the switch ring ( 44 ), and the second cam configuration ( 48 ) can be brought into engagement with a corresponding cam configuration ( 60 ) of a pressure piece ( 54 ) which can be axially moved on the spindle ( 10 ), in order to adjust the percussion means ( 42 ) to a percussion position.

This application claims Paris Convention priority of EP 06 005 591.0 filed Mar. 18, 2006 the complete disclosure of which is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

The invention concerns an electrical hand tool device, in particular, a percussion drill or a drill hammer, comprising a spindle that can be driven by a drive motor and which cooperates at one end thereof with its tool support, and with a percussion means for axially moving the spindle in a percussion position, wherein an adjusting means is provided for adjusting the spindle between the percussion position and a rotary position.

Electric hand tool devices, in particular, percussion drills and drill hammers which have both a percussion position of the spindle, in which the spindle performs an axial translatory motion, and a rotary position, wherein the spindle only executes a rotary drive, have an adjusting means between the two positions. In principle, a combined percussion/rotary position may also be provided, in which the spindle is driven both in a rotary and percussive fashion.

A hand drill of this type comprising a means for switching between the operation modes of drilling and percussion drilling is disclosed e.g. in EP 0 755 756 B1, in which the drill spindle is supported against an axial bearing in the rotary drill operating position, wherein the axial bearing is designed as a rolling bearing and the adjusting instrument acts on the drill spindle via this rolling bearing.

A further embodiment of a corresponding drill is disclosed e.g. in EP 0 399 714 B1 which concerns a force-operated drill, comprising a operation mode changing mechanism for changing the mode of operation of the drill between one mode of operation without percussion drilling and one mode of operation with percussive drilling, wherein the mechanism for changing the modes of operation contains a first rigid and a second elastic component.

It is the underlying purpose of the present invention to present an electric hand tool device, whose adjusting means provides a maximum adjusting path in order to also provide a sufficient adjusting path for percussion means with large notch depression.

SUMMARY OF THE INVENTION

The invention solves this object with an electric hand tool device of this type, wherein the adjusting means comprises a switch ring which is disposed on the spindle and has cam configurations on both end faces, wherein one of the cam configurations can engage into a corresponding cam configuration, which is fixed to the housing, through turning the switch ring, and a second cam configuration can be brought into engagement with a corresponding cam configuration of a pressure piece which can be axially moved on the spindle, in order to adjust the percussion means into a percussion position.

The spindle may thereby exercise axial motion due to engagement of the switch ring in the area of its cam configuration with a cam configuration which is fixed to the housing. This axial motion is blocked in the non-engaged state due to mutual abutment of the cam configurations. A further axial motion is thereby possible, such that the cam configuration of the pressure piece is immersed into a second cam configuration of the switch ring, thereby doubling the axial lift of the spindle.

In this fashion, a corresponding adjustment means can be provided with little construction effort even in electric hand tool devices comprising a percussion means, which require a large axial spindle lift. The engagement between the cam configuration of the switch ring and the cam configuration of the housing is thereby effected by turning the switch ring, such that the curves engage each other through radial rotation.

This double engagement between the switch ring and the cam configuration which is fixed to the housing, and between the pressure piece and the switch ring provides large axial travel of the spindle, thereby realizing a switching process, with which two radial cams of a percussion means can come into engagement with each other.

In a particularly advantageous fashion, the pressure piece may thereby cooperate with a spring which loads the pressure piece away from the switch ring. I.e. the radial cams of the pressure piece and the switch ring are not engaged in the normal basic position. When e.g. the drill of a corresponding percussion drill is put onto a workpiece to be processed, the spindle is axially loaded against the spring force and moves in the axial direction until the radial cams of the percussion means engage with each other and the cam configurations are immersed into each other between the switch ring and the pressure piece, such that when the electric hand tool device is correspondingly switched, percussive or percussion drilling operation is possible, since the spindle can be moved in an axial direction.

When the spindle is no longer axially loaded, e.g. by removing the electric hand tool device from the workpiece, there is no remaining percussive motion of the spindle. In this fashion, an electric hand tool device of this design is much more easy to hold.

The side of the pressure piece opposite the cam configuration may moreover be supported against an axial bearing of the spindle. The axial bearing serves to guide the spindle in the rotary position.

The pressure piece may thereby be preferentially guided in a crank guidance, such that the pressure piece cannot be rotated but perform only a purely translatory motion relative to the housing.

A slide switch may moreover be provided as a switch for the adjusting means, which is provided on the outside on a housing of the electric hand tool device. It may perform e.g., in particular, a radial sliding motion which rotates the switch ring.

Further advantages and features of the invention can be extracted from the other application documents. The invention is explained in more detail below with reference to the drawing.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 shows a section of an inventive electric hand tool device in the rotary position; and

FIG. 2 shows the device in accordance with FIG. 1 in the percussion position.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 shows part of an electric hand tool device comprising a spindle 10 with a support 12 for a tool support, wherein the spindle can be driven via a gear 14 and an electromotor (not shown) which is connected thereto.

The spindle is rotatably disposed in a machine housing 16 via bearings 18, 20 and 22.

The electric hand tool device comprises a percussion mechanism which is designated in total with reference numeral 24. The percussion mechanism 24 has substantially two elements, i.e. the component 26 with a first radial cam 28 and a beater 30 with a second radial cam 32. The two radial cams 28 and 32 of the components 26 and 30 face each other.

The component 26 is thereby pressed onto the spindle 10 and axially abuts a stop 34. The component 26 rotates with the spindle and is axially fixed thereto.

The beater can move axially relative to the spindle 10, but cannot rotate relative to the housing 16. The beater 30 is guided in a beater housing 36 which is inserted and fixed in the machine housing 16.

A spring 40 is also guided in the beater housing 36 and is supported on one side against the beater 30 and on its other side against the beater housing 36, thereby pretensioning it.

FIG. 1 shows an embodiment, in which the radial cams 28 and 32 are not engaged. In this position, a tool clamped into a workpiece support performs a rotary motion only without an axial percussion motion of the spindle 10.

The radial cams are thereby designed such that at least one of the radial cams has a control cam which axially projects towards the other radial cam past the rest of the radial cam. Run-up faces are moreover provided, which permit sliding of the two radial cams on top of each other, thereby permitting overlooking of the control cams provided on one or both radial cams. So-called depressions are provided between the two control cams.

When the two radial cams 28 and 32 engage each other through pressing a tool onto a workpiece to be processed (FIG. 2), the two radial cams engage with each other. Rotation of the component 26 relative to the beater 30 moves the two radial cams relative to each other in a radial direction, such that the control cams cooperate at a certain time, such that the beater 30 is deflected opposite to the direction of the component 26, thereby loading the spring 40. This loading of the spring 40 stores energy in the spring 40. As soon as a depression has been reached on one or both radial cams through further rotation of the radial cams relative to each other, the spring 40 is suddenly relaxed, such that the beater 30 is moved by the released energy towards the component 26. The beater 30 thereby impinges on the component 26 with a predetermined energy and moves it in an axial direction towards the end 12 of the spindle 10. Since the component 26 is fixed to the spindle 10 and abuts, in particular, against the stop 34, the spindle 10 is moved, together with the component 26, in an axial direction. This produces a spindle impact, and a percussion drilling operation can be provided to support drilling.

In order to permit switching from one percussion position to a rotary position and vice versa, an adjusting means is provided at the spindle end opposite to the tool support, which is in total designated by reference numeral 42. The adjusting means 42 comprises an adjusting instrument (not shown), in particular, a slide switch that can be displaced in a radial direction and through which an operator introduces and performs the switching process. A switch ring 44, which has cam configurations 46 and 48 on both end faces, is radially moved relative to the housing through actuating the slide switch, wherein the cam configuration 46 can be brought into engagement with a cam configuration on a component 50 which is fixed to the housing, whose cam configuration is designated with 52. In FIG. 1, the cam configurations 46 and 50 are out of engagement.

FIG. 2 shows the cam configurations 46 and 50 of the switch ring, which are in engagement, and of the component 50 which is fixed to the housing. The adjusting means 42 moreover comprises a pressure piece 54 which abuts against the axial bearing 20 via a spring 56 which supports the spindle 10 during rotary operation. The spring 56 presses the pressure piece 54 towards the percussion mechanism 24, such that in the basic position, the percussion mechanism is in a position in which the radial cams 28 and 32 are out of engagement.

When the adjusting ring is placed into the position shown in FIG. 2 and the spindle 10 end 12 caused to abut a workpiece, the spring force of the spring 56 can be overcome, such that the pressure piece 42 is deflected in the direction of arrow 58 to bring a cam configuration 60, which is disposed on the pressure piece on its end facing the switch ring 44, into engagement with the cam configuration 48 of the switch ring 44. This completely engaged configuration is shown in FIG. 2. The spring 56 is thereby maximally compressed. In order to obtain proper engagement and disengagement of the cam configurations 48 and 60, the pressure piece 54 is guided on a crank guidance, such that it can only exercise a translatory motion relative to the housing 16. When the user of such an electric hand tool device lifts the device from a workpiece to be processed, the pressure on the springs 56 and 40 is consequently reduced, the springs relax, and the percussive motion of the spindle is stopped.

An arrangement as shown in the above figures is advantageous in that the cam configurations 46 and 52 and the cam configurations 48 and 60 engage each other in such a manner as to provide a relatively large lift for the spindle 10 (clearly visible in FIGS. 1 and 2), wherein the spindle 10 in FIG. 2 is clearly shifted to the left in the plane of the drawing. This large axial motion that the spindle 10 can then perform permits use of a percussion mechanism with high notch depth or high curvature of the radial cams 28 and 32.

The invention increases the lift motion without changing the operation of a slide switch. 

We claim:
 1. An electric hand tool device, a percussion drill, or a drill hammer, the device comprising: a housing; a drive motor disposed in said housing; a spindle cooperating with said drive motor and having an end for engagement with a tool support; percussion means cooperating with said spindle for axially displacing said spindle in a percussion mode; a first cam fixed to said housing; a pressure member having a second cam, said pressure member structured for axial displacement along said spindle; and a switch ring disposed on said spindle, said switch ring having a third cam on a first end face thereof and a fourth cam on a second end face thereof, said switch ring being structured for turning to bring said third cam into engagement with said first cam and said fourth cam into engagement with said second cam, wherein said switch ring is turned from a rotary position into a percussion position.
 2. The electric hand tool device of claim 1, further comprising a spring cooperating with said pressure member to urge said pressure member away from said switch ring.
 3. The electric hand tool device of claim 1, wherein said spindle has an axial bearing supporting said pressure member at a side thereof opposite to said second cam.
 4. The electric hand tool device of claim 1, wherein said pressure member is guided in a cam such that it cannot be rotated relative to said housing.
 5. The electric hand tool device of claim 1, further comprising a slide switch for rotating said switch ring. 